1. Field of the Present Disclosure
This disclosure relates generally to refreshable tactile displays for Braille text and graphics for the blind, and, more particularly, relates to an easily cleaned Braille module utilizing tactile pins that can absorb strong downward forces without damage to the pins or the actuation mechanism.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Hannen et al., U.S. Pat. No. 4,191,945 discloses an electromechanical apparatus for setting up and erasing alpha-numeric characters or other symbols in Braille by means of a tactile display. Dot pins simulating Braille are supported for movement within holes in a display plate to a position protruding therefrom to form tactile characters and for retraction to a withdrawn position flush with the surface of the display plate. Solenoid-operated plungers are arranged to selectively project the dot pins. Latch elements are movable by energizing the solenoid to a position to support the plungers in their operative position, a common support for the latch elements movable in a plane perpendicular to the axis of the support plungers to remove the latch elements, and spring means for restoring the support plate to its initial position.
Tetzlaff, U.S. Pat. No. 4,283,178 An electromechanical braille cell is disclosed wherein each cell includes six braille indicia formed by the free ends of a vertical stack of cantilever supported piezoelectric reeds. Applying an operating potential to a respective reed causes the reed to bend about a fulcrum at the supported root end of the reed causing the free end to deflect in such a manner as to cause the indicia rod to protrude through an opening in the reading surface of the braille cell. Simultaneous energization of one or more of the reeds in the respective stack defines a given braille character sensed by the operator. The free ends of the reeds are tiered in pairs in a stair step configuration so that the sensing rods from a lower pair of reeds pass by the free end portions of the reeds of a higher step. The upper reed of each pair of reeds is notched to allow passage of the sensing rod associated with the lower reed of that pair of reeds.
Petersen, U.S. Pat. No. 4,871,992 discloses a tactile display according to which a touch pin is selectively movable relative to a reference surface. An electromagnet distant from the reference surface has spaced poles of opposite, selectively reversible, polarity. A cam rotatable about an axis transverse to the reference surface has an integral permanent magnet with similarly spaced poles of opposite polarity equidistant from the axis of rotation. The cam is rotatable between an active position at which its respective poles are attached to and positioned adjacent the poles of the electromagnet and an inactive position at which the reversed poles of the permanent magnet are attracted to and positioned adjacent the opposite poles of the electromagnet. A touch pin has a longitudinal axis transverse to the reference surface and includes a follower end engagable with the cam and a tip end distant from the follower end. The pin is movable on the cam between a first position raised above the reference surface when the cam is in the active position and a second position not projecting beyond the reference surface then the cam is in the inactive position. A plurality of touch pins and associated mechanisms can be combined into a matrix to form a tactile display unit and a plurality of such units can be provided in a console and electronically driven in an intelligent fashion to provide the user with various forms of tactile information.
Tani et al., U.S. Pat. No. 5,449,292 discloses a tactile reading device including sensing rods that are supported to be vertically movable, piezo-electric actuating elements disposed in the vertical direction such that their free end portions are directed upward, and pushing-up cams having first levers which are axially and pivotally supported on support rods provided at an upper position of the free end portions of the piezo-electric actuating elements, extending downward from the support rods, and having side surfaces at distal end portions thereof which are freely abutted against the free end portions of the piezo-electric actuating elements, and second levers extending horizontally from the support rods and freely mounting, on their mounting planes, lower end portions of the sensing rods corresponding to the piezo-electric actuating elements.
Gilkes et al., U.S. Pat. No. 5,580,251 discloses a Braille display device which comprises: a plurality of cavities; and circuitry to individually excite the plurality of cavities. The plurality of cavities contain a positive and a negative electrode and are filled with a quantity of polar organic gel sensitive to electric fields. The cavities are sealed by an elastomeric film. The elastomeric film is held generally flat, by its own tension, in the absence of any voltage applied to the electrodes in the plurality of cavities. The display device can also include circuitry to determine whether the cavity has been touched by a person who is reading the display. The display device can also include circuitry to individually vibrate each cavity. Other devices, systems and methods are also disclosed.
Decker, U.S. Pat. No. 5,685,721 discloses a refreshable Braille cell display using a single moving part per tactile element. Tactile elements, formed from stainless steel tubing, are assembled in densely arranged modules. Lower ends of the tactile elements extend beneath the modules and are in contact with a pressurized medium. Shape memory alloy actuators are positioned in the tactile elements, isolated from any motion or flow in the pressurized medium. When a pressurized medium is delivered through a port in a tactile element, the actuator extends upward, thereby forcing the upper portion of the tactile element through a hole in the user contact surface. In that state the tactile element indicates information. When the tactile element is activated, current flows from an electrical contact at the lower end of the tactile element, through the actuator, and into the outer tube of the tactile element. The actuator heats, due to electrical resistance, contracts and exerts a downward force on the pressure medium. The upper portion of the tactile element is drawn below the user contact surface, indicating the absence of information. Distributed pulse width modulation allows instantaneous power requirements to be minimized, and only low safe voltages are needed to operate the array. By applying a bias force to all actuators via a common reservoir of either pneumatic or hydraulic pressure, the design is simplified, and reliability is increased. When integrated with a computer, the refreshable tactile array of elements gives users access to full computer generated screens of text and graphical information in real time.
Becker et al., U.S. Pat. No. 6,417,821 discloses a tactual computer monitor including rows and columns of rectangular cells. Each cell includes four rows and two columns of movable pins which are felt and read by a blind person. The pins are driven by electromechanical impact drivers and are held in position by resilient elastomeric cords. The impact drivers are carried on a bi-directional print head which travels beneath the movable pins. An erasing mechanism is provided to positively drive the pins downwardly to erase the characters produced by the print head.
Gupta, U.S. Pat. No. 6,459,364 discloses a method of communicating electronic information via a display device having a matrix of movable tactile elements. The method includes displaying a representation of a file containing hypertext links on a first portion of the matrix, and displaying a list of the hypertext links on a second portion of the matrix. The representation may include graphical elements and text symbols such as Braille.
Petersen, U.S. Pat. No. 6734,785 discloses a tactile display system that includes a housing containing a tactile pin movable axially transverse of a reference surface and an actuator mechanism engagable therewith for selective movement between raised and lowered positions. An elongated electromagnet distant from the reference surface is aligned with the tactile pin and has spaced poles of opposite, selectively reversible, polarity. A generally spherical rotatable positioning member being a permanent magnet having a peripheral surface which is partially a spherical surface and partially a truncated surface has an axis of rotation coaxial with the tactile pin and the electromagnet and is responsive to operation of the electromagnet, being movable between a first position at which the spherical surface faces the tactile pin, causing positioning of the tactile pin at the raised position and a second position at which the truncated surface faces the tactile pin causing positioning of the tactile pin at the lowered position.
Prince et al., U.S. Pat. No. 6,743,021 discloses a refreshable display system with a flexible surface, with one application being a refreshable Braille display systems for use as a monitor for computer systems.
Roberts et al., U.S. Pat. No. 6,776,619 discloses an apparatus and method for refreshable tactile display, the apparatus being preferably embodied as a rotating-wheel refreshable Braille reader. The reader includes a housing having a reading aperture with a rotatable wheel assembly maintained therein so that a display surface of a rotating wheel passes the reading aperture. The wheel has endless rows of openings defined therethrough to the display surface, a pin held in each opening and freely movable therein. Actuators, at least equal in number to the rows of openings but substantially fewer in number than the openings, are held at a static location relative to the wheel for selectively moving pins in the rows so that Braille characters are arrayed at the display surface after passing the static location. Braille characters are thus streamed across the reading aperture of the housing.
Souluer, U.S. Pat. No. 6,827,512 discloses a refreshable display unit with a housing, a plurality of refreshable cells housed in the housing, the cells having a guide block with at least six holes, six motors each with a coupler which may be rotated by the motor, a pin fastened to each coupler and extending into engagement with one of the holes of the guide block, and a stop mounted on each coupler for engaging stop elements mounted on the housing for limiting the rotation of the coupler, the placement of the stop elements on the housing being such that it controls the height extension of the pin fastened to the coupler with respect to the guide block, the unit further having a connector for connecting the display unit to the electronic means of a computer. A unit may have a plurality of keys for inputting a character, including at least two sets of keys, a first set being used when the keyboard is oriented in a first direction and a second set being used when the keyboard is oriented in a second direction.
Goldenberg, U.S. Pat. No. 6,902,403 discloses a Braille pin that has three parts sharing a common longitudinal axis. A first part has a first breadth and includes a rounded tip felt by a user. A second part has a noncircular transverse cross-section and has a breadth greater than the first breadth. A first shoulder is formed by the juncture of the first and second parts. A third part has a third breadth less than the second breadth. A second shoulder is formed at the juncture of the second and third parts. A pinhole has first, second, and third sections that respectively receive the first, second and third parts of the pin. The first shoulder limits upward pin travel by abutting an overhang at the juncture of the first and second pinhole sections. The second shoulder limits downward pin travel by abutting a step at the juncture of the second and third pinhole sections.
Roberts et al., U.S. Pat. No. 7,009,595 discloses an apparatus and methods for an extended refreshable tactile graphic display, the apparatus including an array of pins at a display surface, with pin setting actuators and a display surface matrix preferably being separable units. The display matrix is provided by stacked functional layers having functions including temporary pin retention and pin locking.
Schleppenbach et al., U.S. Pat. No. 7,018,209 discloses various apparatus and methods for an actuator and display using one or more shape memory springs. A shape memory spring is heated and urges a pin to a first or extended position. The pin may be supported in the first position by a supporting mechanism. The shape memory spring is heated electrically, and in some embodiments under the control of a processor. The present invention may be used to display information provided in a user interface from a computer program, including text, numerical data, and graphical images.
The related art described above discloses refreshable tactile displays which can produce Braille text and graphics using tactile pins controlled by various types of actuator devices. However, the prior art fails to disclose a refreshable tactile display that uses compressible tactile pins and a module structure that is easily cleaned. The present disclosure distinguishes over the prior art providing these and other currently unknown advantages as described in the following summary.